The present invention relates to a non-impact electrothermic recording material, and more particularly to a nonimpact electrothermic image transfer recording material for use with noiseless typewriters, computer output apparatus and facsimile apparatus.
Conventionally, a variety of non-impact electrothermic recording materials have been proposed.
For example, in U.S. Pat. No. 4,103,066, there is proposed a recording material in the shape of a non-impact printing ribbon consisting of an image transfer layer and an electrically resistant layer comprising polycarbonate resin and electroconductive carbon black. This recording material, however, has the shortcoming that the polycarbonate resin employed in the electrically resistant layer has a thermally deforming temperature as low as 120.degree. C. to 130.degree. C., so that part of the resin is melted and adheres to the styli of a recording electrode during recording operation and eventually the quality of printed images is degraded and the life of the styli is shortened.
In Japanese Laid-Open Patent Application 56-93585, there is proposed a recording material consisting of a support having a thickness of about 5 .mu.m, made of expensive stainless steel, or an aluminum layer having a thickness of 0.1 .mu.m, which serves as an electroconductive layer as well, an electrically resistant layer formed on the support, which consists of a resin film comprising electroconductive carbon and a resin in which the electroconductive carbon is dispersed, and a layer of SiO/Cr, SiCo, or Al.sub.2 O.sub.3 formed on the resin film, and an image transfer layer formed on the electrically resistant layer. This recording material has the shortcoming that the quality of dots is not good.
In U.S. Pat. No. 4,536,437, there is proposed a three-layered type non-impact electrothermic image transfer recording material which comprises a base layer (electrically resistant layer), an intermediate layer and an ink layer. Since the intermediate layer comprises a resin component and carbon, it is difficult to decrease the electric resistivity of the intermediate layer. Therefore the necessary voltage for recording is as high as 100 to 200 V.
The above-mentioned non-impact electrothermic image transfer recording materials have the common shortcoming that the quality of printed images is easily affected by the surface smoothness of a recording sheet, so that it is difficult to obtain dots in good shape when a recording sheet having a rough surface is employed.